Method of die casting



Nov. 10,1925. 1,561,233

. S. C. HOEY METHOD OF DIE CASTING Filed July 13. 1923 57 3; 2a 21 i 23 L25 22 A a 10. J 4 4. 4 19 11 H J HIIHI r l H J8 a 4 WIT ESSES: 'F/ .8. INVENTOR Q a2 a1 50/77118/ G. Hoey.

Patented Nov. v10, 1925.

VUNITED- STATES 1,561,233 PATENT. OFFICE.

SAMUEL C. HOEY, 0F WILKINSBURG, PENNSYLVANIA, ASSIGNOR T0 WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

METHOD or DIE casrme.

Application filed July 13, 1923. Serial No. 651,222.

To all whom it may concern:

Be it known that I, SAMUEL C. Hoar, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Methods of Die Casting, of which the following is a specification;

My invention relates to a process and apparatus for casting metal bodies, more especially for casting metal bodies of irregular cross-section, such as rotors for dynamo electric machines.

It is among the objects of my invention to provide a method of forming rotors by casting them under pressure which shall be simple and inexpensiveto perform in conjunction with a pressure casting device such as I have described in my copending application Serial No. 641,220, filed July 13, 1923.

Bodies cast under pressure in metal molds have a tendency to shrink because of the cooling of the metal, especially in bodies having complicated shapes and irregular cross-sections, such as rotors having the end rings and conductor bars cast integral therewith. The end portions, especially the end member remote from the charging end of the mold has a tendency to become distorted on account 'of the rapid cooling of the metal at this end, which sets the metal prematurely so that thepressure exerted on the molten substance at the charging end no longer takes effec \My resent invention is directed to a means or overcoming'this difiiculty by utilizing one or more metal strips which are of ring shape or are spirally wound, and are located at one or both ends of the moldand around which the metal is cast. The strips or inserts prevent the formation of blow holes and collapse of the surface, as by this means the cast metal is chilled in the center as well as the outside surfaces which contact with the mold. I

In the accompanying drawing constituting a part hereof and in which like reference characters designate like parts,

Fig. 1 is a vertical sectional View of a pressure casting device utilized in carrying out the objects of my invention, and

Fig. 2 is a fragmentary portion of a section through the mold and a part of the finished casting.

integral actuated y the member 17 which breaks off Referring to Fig. 1, the device therein illustrated consists 'of a base 1', a pot 2,

a mold 3 and a pressure clamp 4, the latter being manually operated by the usual type of hand operated clamping screw 5. T e base 1 is adapted to be secured to a foundation 6 by a plurality of bolts (not shown) extending through the openings 7 of the bottom flange 8 thereof. -The pot 2 is secured by a similar flange 9 to,.. the base 1 and the mold 8 is mounted 'on the pot 2 by 'means of a base plate 10 having port holes 11 communicating with a reservoir 12 in the pot 2, in which is disposed a piston 13, having a Weight 14 associated therewith, the piston being adapted to move vertically in the reservoir 12 when actuated at its joint 15 by pressure actuating means (not shown A lever 16 having an actuating member 1 such as a liquid pressure actuated cylinder associated with the end thereof, is pivoted by a rivet or bolt 18 to an extending portion 19 of the pot/2.

The base plate 10 and the pressure clamping plate 4 are provided with annular extending portions 21 'to provide annular spaces 22 at the respective ends of the mold. A laminated structure 23, constituting the iron portion of a rotor for a dynamo electric machine, is clamped between the plates 4 and 10, as illustrated. A metal insert 24,

comprising a spirally wound strip ofaluminun: metal or other material having the same characteristics as the metal to be cast, is inserted in the space 22 on top of the rotor 23. The insert 24 becomes an integral part of the casting when the metal has been formed therearound and functions to cool the centers of the ring portions formed in the space 22 during the casting operation, thereby preventing blow, holes or excessive shrinkage'on the outer surface of the rin portions. The clamping plate 4 is provided with vent holes 27 The operation of the device is briefly as follows: The reservoir 12 is filled with a molten metal which is forced through the ports 11 into the mold 3 filling the annular spaces 22 and the vertical slots 25 and forming around the strip24: making the latter an art thereof. The lever 16 is then the sprues formed in the ports. The clamping plate 4 is then removed giving access to the rotor which is taken out of the mold. The operation may then be repeated.

It is evident from-the above descriptionof my invention that rotors cast in accordance therewith will be free from blow holes and surface irregularities on account of the chilling effect of the inserted strip which counteracts the shrinkage caused'by the cooling of the outer surface of the ring portion. This method further provides a simple and expedient means for roducing castlngs of uniform quality, w ich are fully formed and which require no machining to prepare them for use.

Although I have described a specific embodiment of my invention, it willbe obvious to those skilled in the art that various changes may be made in the shape and the amount of the strip used and the manner in which it is inserted or'located within the mold or body in which the metal is cast without departing from the spirit hereof.

I claim as my invention 1. The method ofcasting metal bodies which comprises placing a laminated struc ture in a mold, acing a metal insert in a recess of said structure and charging said mold with molten'metal under pressure to envelop said insert and to form a casting integral with said laminated structure.

2. The method of casting metal bodies which comprises placing a metal insert in a mold and charging said mold with molten metal under pressure to envelop said insert and to form a casting integral therewith, said cast metal having the same characteristics as the said insert.

3. The method of casting metal bodies which comprises inserting a laminated body in the matrix of a mold, lacing a metal insert on said body and charging said mold with molten metal under pressure to envelop said laminated body and insert to form an integral structure.

4. The method of casting metal bodies which comprises inserting a laminated body in the matrix of a mold placing a metal insert comprising a spirally wound strip on said body and charging said mold with molten metal under pressure to envelop said laminated body and insert to form an inte- .gral structure.

In testimony whereof, I have hereunto subscribed my name this 2nd day of July 1923.

SAMUEL C. HOEY. 

